Golf club set with optimal center of mass

ABSTRACT

A set of golf club irons which have three parallel slots disposed in the back side of each club head, where the top slot is shorter than the middle slot, which in turn is shorter than the bottom slot, and where the depth of the middle slot remains the same for all clubs, but the depth of the top slot decreases progressively and the depth of the bottom slot increases progressively from the lesser lofted iron to the higher lofted iron, such that the center of mass is progressively higher over the set from the lesser lofted iron to the higher lofted iron.

BACKGROUND OF THE INVENTION

[0001] This invention relates generally to the field of golf clubs, and more particularly to the field of golf clubs known as irons and wedges. Even more particularly, the invention relates to a correlated and ordered set of irons and wedges where the center of mass of each individual club is optimized for desired performance, each club having a slightly different center of mass location.

[0002] Playing good golf requires, among many other variables, the ability to produce a repetitive and consistent swing with any of the clubs. Individual clubs will vary in loft angle, lie angle, shaft length, with the lower numbered irons being designed to strike the ball farther with a flatter trajectory and the higher numbered irons and wedges being designed to strike the ball a shorter distance but with a higher trajectory. An important consideration in ball flight and ball action, i.e., the amount of back spin imparted to the ball upon it being struck, is the center of mass or center of gravity of the club head. For the wedges and higher numbered irons, it is most desirable that the center of mass be higher in the club head in order to produce maximum back spin and to assist in bringing the ball up quickly in a high arc. For the lower numbered long irons, however, it is most desirable that the center of mass be low since the ball does not need to be brought up in a high arc and less spin is usually desired. It is also desirable that the overall differences between the club heads be minimized, such that the golfer can produce a repetitive swing no matter which club is chosen.

[0003] There have been various attempts made in the art to provide sets of golf clubs with varying centers of mass. For example, in U.S. Pat. No. 4,923,197, issued in 1990 to Schacht, a set of clubs is shown where horizontal weight bars are mounted externally onto the back sides of the club heads, with the bar located nearer the top edge for the wedges and higher numbered clubs and located nearer the sole for the lower numbered clubs. U.S. Pat. No. 5,722,900, issued in 1998 to Sung, shows a set of clubs each having a curved back wall connected to the sole of the club head, where the vertical location of the center of gravity is altered by varying the depth of chamber formed between the back wall and the striking face.

[0004] It is an object of this invention, therefore, to provide a correlated and ordered set of golf clubs where the center of mass is optimized within each club head dependent on the striking characteristics desired for the particular club, where the optimization is achieved in a consistent manner without extensive alteration of the configuration of the club head. It is a further object to provide a means to optimize the center of mass on each club of an existing set of clubs, where the alteration to the club head does not negatively impact the configuration of the club head. These and other objects not expressly set forth at this time but which will become obvious from the following disclosure are accomplished by providing a series of three parallel slots on the back side of the club heads, the slots having varying depths dependent on the desired location of the center of mass relative to the particular club.

SUMMARY OF THE INVENTION

[0005] The invention comprises in general a correlated and ordered set of golf clubs or golf club heads, and in particular a correlated and ordered set of irons and wedges, typically designated by the numbers 2 through 9 and by the terms pitching wedge, sand wedge and lob wedge (or 10, 11, 12). Each club head is provided with three, generally horizontal, parallel slots on the back side of the club head, with the slots progressing in length from top to bottom. The slots are cut into the body of the club head such that the top slot extends approximately 1.5 inches, the middle slot extends approximately 1.95 inches, and the bottom slot extends approximately 2.4 inches. The middle slot is at a fixed depth for all the clubs, while the depth of the top and bottom slots varies in an ordered manner depending on the loft of the particular club. By altering the depth of the top and bottom slots, the center of mass of the club head is optimized for each club without drastically altering the look and feel of an individual club and of the set of clubs overall. For the more lofted, higher numbered clubs, the depth of the top slot is reduced and the depth of the bottom slot is increased relative to the lesser lofted clubs in order to raise the center of mass in the vertical direction. For the lesser lofted, lower numbered clubs, the depth of the top slot is increased and the depth of the bottom slot is decreased relative to the greater lofted clubs in order to lower the center of mass.

[0006] In other terms, the invention comprises a set of correlated golf club irons, each of said irons having a different loft and a different center of mass, and each of said irons having three slots generally horizontal disposed on the back side thereof to define a top slot, a middle slot and a bottom slot; wherein the depth of at least one of said slots in any one of said irons is different from the depth of the corresponding slot in each of the remaining said irons of said set; and wherein the particular combination of depths of said slots for each said iron produces a progressively higher center of gravity corresponding to progressively increasing loft.

[0007] In still other terms, the invention comprises an improvement in a correlated set of golf club heads with different lofts forming a set of golf clubs, each such golf club of said golf club set having a club head comprising a striking face, a top edge, a back side, a sole plate, a loft and a center of mass, the improvement comprising three slots disposed on said back side of each of said golf club heads, said slots disposed generally parallel to said sole plate and consisting of a top slot, a middle slot and a bottom slot; wherein said top slot is shorter than said middle slot, and said middle slot is shorter than said bottom slot; wherein said middle slot has the same depth for each of said golf clubs over said set of golf club heads; wherein said the depth of said top slot decreases or remains the same over said set of golf club heads as said lofts increase; wherein said depth of said bottom slot increases or remains the same over said set of golf club heads as said lofts increase; and wherein no two golf club heads of said set of golf club heads have the same depths for both said top slot and said bottom slot; such that said center of mass of each of said golf club heads is progressively higher over said set of golf club heads as said lofts increase, and such that each of said golf club heads has a different center of mass.

BRIEF DESCRIPTION OF THE DRAWINGS

[0008]FIG. 1 is a rear view of a representative club head showing the slots disposed in the back side of the club.

[0009]FIG. 2 is a cross-sectional view of a representative club head taken along line II-II of FIG. 1, where the variation in depth of the top and middle slots and the variation in the location of the center of mass of the club head is illustrated.

DETAILED DESCRIPTION OF THE INVENTION

[0010] With reference to the drawings, the invention will now be described in detail with regard for the best mode and the preferred embodiment. The invention comprises in general a correlated and ordered set of golf club irons and wedges, or the corresponding club heads, where the center of mass of each club head is optimized for the most desirable ball striking characteristics, such that the center of mass is higher for the more lofted clubs and lower for the less lofted clubs.

[0011] As seen in FIGS. 1 and 2, a club head 10 comprises a toe 11, heel 12, hosel 13, striking face 14, top edge 15, leading edge 16, trailing edge 17, back side 18 and sole plate 19. Such general constructions for club heads are well known in the art. Three parallel slots, channels or grooves 20 are disposed on the lower portion of the back side 18 of the club head. The slots 20 extend generally horizontally and are generally parallel to the sole plate 19 or trailing edge 17 of the club head 10. The slots 20 are separated by lands 21 which comprise the portions of the back side 18 disposed between the slots 20. The slots 20 are most preferably generally rectangular in configuration and in cross-section, although other configurations and cross-sections are possible without departing from the spirit of the invention. The slots 20 are preferably of three different lengths, with the top slot 22, i.e., the slot 20 closest to the top line 15, being the shortest and the bottom slot 24, i.e., the slot 20 closest to the trailing edge 17 or sole plate 19 being the longest. Most preferably, top slot 22 is approximately 1.5 inches in length, middle slot 23 is approximately 1.95 inches in length, and bottom slot 24 is approximately 2.4 inches in length. Each slot 20 is preferably approximately 0.25 inches in width and the width of the lands 21 separating the slots 20 is preferably approximately 0.06 inches.

[0012] As seen in FIG. 2, which shows the most preferred depths, the depth of the middle slot 23 remains constant on each club head 10 and is preferably approximately 0.040 inches, while the depths of the top slot 22 and the bottom slot 24 vary as shown by the dashed lines between preferably approximately 0.030 and 0.060 inches. The variation in depth is shown in the following table. Measurements are given in inches and the club number designations 10, 11 and 12 correspond to the pitching wedge, sand wedge and lob wedge, respectively. TABLE 1 Depth in Inches of Slots Relative to Club Number 2 3 4 5 6 7 8 9 10 11 12 Top Slot 0.060 0.055 0.050 0.050 0.045 0.045 0.040 0.040 0.035 0.035 0.030 Middle Slot 0.040 0.040 0.040 0.040 0.040 0.040 0.040 0.040 0.040 0.040 0.040 Bottom Slot 0.030 0.035 0.035 0.040 0.040 0.045 0.045 0.050 0.050 0.055 0.060

[0013] As can be seen, the depth of the top slot 22 decreases progressively in certain fashion from the less lofted 2-iron to the more lofted lob wedge, while the depth of the bottom slot 24 increases progressively in certain fashion from the less lofted 2-iron to the more lofted lob wedge, such that each individual club has a distinct combination of slot depths. For a given club head 10 in the set, the depth of the top slot 22 is shallower or equal for any club head 10 of lesser loft, and is deeper or equal for any club head 10 of greater loft. The depth of the bottom slot 24 for a given club head 10 in the set is deeper or equal for any club head 10 of lesser loft, and is shallower or equal for any club head 10 of greater loft. Where two club heads 10 adjacent in terms of progressive loft have top slots 22 of equal depth, the bottom slots 24 will be of different depth, and where any two adjacent club heads 10 have bottom slots 24 of equal depth, the top slots will be of different depth, thereby providing that no two club heads 10 of the set will have matching depths for both the top slots 22 and the bottom slots 24 at eh same time, thus insuring that the centers of mass 30 for each club head 10 will be different from every other club head 10.

[0014] The variation in depths for the top slots 22 and bottom slots 24 affects the location of the center of mass 30 for each club head 10. For the highest lofted lob wedge, the bottom slot 24 is deeper and the top slot 22 is shallower, and therefore the center of mass 30′ is higher than for the other club heads 10. Thus for the higher numbered, more lofted clubs, the center of mass 30 is relatively high such that greater spin is imparted on the golf ball when it is struck and the ball is brought up at a higher arc. For the least lofted 2-iron, the top slot 22 is deeper and the bottom slot 24 is shallower, and therefore the center of mass 30″ is lower than for the other club heads 10. Thus for the lower numbered, less lofted clubs, the center of mass 30 is relatively low such that less spin is imparted and the ball is not brought up quickly. Thus the center of mass 30 is progressively elevated over the set of club heads 10 from the lowest loft to the highest loft.

[0015] The slots 20 may be formed in the club heads 10 at time of manufacture, or they may be provided on the club heads 10 at any time by machining or other suitable metal removing technique. A golfer may thus adjust the centers of mass 30 in a used set of clubs in order to optimize the center of mass 30 in each individual club head 10. The invention may be provided in golf club sets of greater number than illustrated, for example where a 1-iron is present, or in golf club sets of lesser number, for example for a set of irons with no wedges or for a set of wedges.

[0016] It is understood that equivalents and substitutions for certain elements set forth above may be obvious to those skilled in the art, and therefore the true scope and definition of the invention is to be as set forth in the following claims. 

I claim:
 1. A set of correlated golf club irons, each of said irons having a different loft and a different center of mass, and each of said irons having three slots generally horizontal disposed on the back side thereof to define a top slot, a middle slot and a bottom slot; wherein the depth of at least one of said slots in any one of said irons is different from the depth of the corresponding slot in each of the remaining said irons of said set; wherein the particular combination of depths of said slots for each said iron produces a progressively higher center of gravity corresponding to progressively increasing loft.
 2. The set of irons of claim 1, wherein said top slot is shorter than said middle slot, and said middle slot is shorter than said bottom slot.
 3. The set of irons of claim 1, wherein the depth of said middle slot is the same in each of said irons.
 4. The set of irons of claim 2, wherein the depth of said middle slot is the same in each of said irons.
 5. The set of irons of claim 1, wherein the depth of said top slot for any one of said irons is shallower or equal relative to the depth of said top slot in any of said irons having a lesser loft and is deeper or equal relative to the depth of said top slot in any of said irons having a greater loft.
 6. The set of irons of claim 2, wherein the depth of said top slot for any one of said irons is shallower or equal relative to the depth of said top slot in any of said irons having a lesser loft and is deeper or equal relative to the depth of said top slot in any of said irons having a greater loft.
 7. The set of irons of claim 3, wherein the depth of said top slot for any one of said irons is shallower or equal relative to the depth of said top slot in any of said irons having a lesser loft and is deeper or equal relative to the depth of said top slot in any of said irons having a greater loft.
 8. The set of irons of claim 4, wherein the depth of said top slot for any one of said irons is shallower or equal relative to the depth of said top slot in any of said irons having a lesser loft and is deeper or equal relative to the depth of said top slot in any of said irons having a greater loft.
 9. The set of irons of claim 1, wherein the depth of said bottom slot for any one of said irons is deeper or equal relative to the depth of said bottom slot in any of said irons having a lesser loft and is shallower or equal relative to the depth of said bottom slot in any of said irons having a greater loft.
 10. The set of irons of claim 2, wherein the depth of said bottom slot for any one of said irons is deeper or equal relative to the depth of said bottom slot in any of said irons having a lesser loft and is shallower or equal relative to the depth of said bottom slot in any of said irons having a greater loft.
 11. The set of irons of claim 3, wherein the depth of said bottom slot for any one of said irons is deeper or equal relative to the depth of said bottom slot in any of said irons having a lesser loft and is shallower or equal relative to the depth of said bottom slot in any of said irons having a greater loft.
 12. The set of irons of claim 4, wherein the depth of said bottom slot for any one of said irons is deeper or equal relative to the depth of said bottom slot in any of said irons having a lesser loft and is shallower or equal relative to the depth of said bottom slot in any of said irons having a greater loft.
 13. The set of irons of claim 5, wherein the depth of said bottom slot for any one of said irons is deeper or equal relative to the depth of said bottom slot in any of said irons having a lesser loft and is shallower or equal relative to the depth of said bottom slot in any of said irons having a greater loft.
 14. The set of irons of claim 6, wherein the depth of said bottom slot for any one of said irons is deeper or equal relative to the depth of said bottom slot in any of said irons having a lesser loft and is shallower or equal relative to the depth of said bottom slot in any of said irons having a greater loft.
 15. The set of irons of claim 7, wherein the depth of said bottom slot for any one of said irons is deeper or equal relative to the depth of said bottom slot in any of said irons having a lesser loft and is shallower or equal relative to the depth of said bottom slot in any of said irons having a greater loft.
 16. The set of irons of claim 8, wherein the depth of said bottom slot for any one of said irons is deeper or equal relative to the depth of said bottom slot in any of said irons having a lesser loft and is shallower or equal relative to the depth of said bottom slot in any of said irons having a greater loft.
 17. The set of irons of claim 13, wherein the depths of said top slots range from approximately 0.060 to 0.030 inches, and the depths of said bottom slots range from approximately 0.030 to 0.060 inches.
 18. The set of irons of claim 17, wherein the depth of said middle slot is approximately 0.040 inches.
 19. The set of irons of claim 18, wherein said top slot is approximately 1.5 inches in length, said middle slot is approximately 1.95 inches in length and said bottom slot is approximately 2.4 inches in length, and wherein said slots are approximately 0.25 inches in width and are separated from each other by approximately 0.06 inches.
 20. In a correlated set of golf club heads each with different lofts and forming a set of golf clubs, each such club head comprising a back side, a sole plate, a loft and a center of mass, the improvement comprising: three generally parallel slots disposed on said back side of each of said golf club heads, said slots disposed generally parallel to said sole plate and consisting of a top slot, a middle slot and a bottom slot; wherein said top slot is shorter than said middle slot, and said middle slot is shorter than said bottom slot; wherein said middle slot has the same depth for each of said golf clubs over said set of golf club heads; wherein said the depth of said top slot generally decreases over said set of golf club heads as said lofts increase; wherein said depth of said bottom slot generally increases over said set of golf club heads as said lofts increase; and wherein no two of said golf club heads of said set have the same depths for both said top slot and said bottom slot; such that said center of mass of each of said golf club heads is progressively higher over said set of golf club heads as said lofts increase, and such that each of said golf club heads has a different center of mass.
 21. The set of irons of claim 20, wherein the depth of said top slot for any one of said golf club heads is shallower or equal relative to the depth of said top slot in any of said golf club heads having a lesser loft and is deeper or equal relative to the depth of said top slot in any of said golf club heads having a greater loft, and wherein the depth of said bottom slot for any one of said golf club heads is deeper or equal relative to the depth of said bottom slot in any of said golf club heads having a lesser loft and is shallower or equal relative to the depth of said bottom slot in any of said golf club heads having a greater loft. 